The Sumoylation of General Transcription Factors Regulates Transcription in Saccharomyces cerevisiae

Sumoylation is a post-translational modification which primarily targets nuclear substrates and can result in altered target protein activity, stability, conformation, and/or localization. Out of the six general transcription factors (GTFs), we have determined that transcription factor IID (TFIID) and transcription factor IIF (TFIIF) are targets of sumoylation. The functional impacts of GTF sumoylation were assayed using strains with elevated or reduced TFIID or TFIIF sumoylation. Using chromatin immunoprecipitation (ChIP), we found that GTF sumoylation does not substantially impact GTF-chromatin interactions but can impact the promoter-wide sumoylation level. Notably, TFIID and TFIIF sumoylation enhances RNAPII recruitment at various promoters likely via altered protein-protein interactions but does so through seemingly distinctive mechanisms. A ChIP-seq and an RNA-seq revealed that reduced GTF sumoylation results in diminished RNAPII density at thousands of genes but this change does not substantially impact steady-state mRNA levels. This research has uncovered novel characteristics of transcriptional regulation in eukaryotes.